High CPU usage (+120%) when Youtube player interface is showing. Normal?

[Panino]

First I thought it was Picture-in-Picture, but looking closer the problem is player interface.
When it's showing the CPU usage skyrockets.

Is this expected or not?

EDIT: testing more, I found that CPU usage is stabilizes around +80%. But if you're watching a play list and if you let that list menu open, then the CPU usage goes to +120%.

[DoctorG]

@Panino Perhaps a GPU driver interference.

1. Please open vivaldi://gpu , copy text and post here with </> button.
2. Try without extensions to reduce impact of these:
   Start in shell vivaldi --disable-extensions
3. Open Settings → Webpages → tick "Use of Hardware Acceleration" and restart Vivaldi.

[mib2berlin]

@Panino
Hi, do you use the Vivaldi task manager (Shift+Esc)?
I test PiP and it show ~30% of 800% as my i5 4 core have 8 threads.
Video encoding on the GPU is not supported on Linux so it seams normal if it use one thread + on video streaming.

Cheers, mib